Tooth and adaptor assembly for a dipper bucket

ABSTRACT

A tooth and adaptor assembly is provided for a dipper bucket. The assembly includes an adaptor having a rear portion for attaching to a dipper bucket, a tooth capable of releasable attachment to the adaptor and a retainer pin for securing the tooth to the adaptor. The adaptor has a tapered intermediate portion that narrows to a rectangular front portion and a planar surface on a portion of its intermediate portion. A groove traverses the planar surface, and extends perpendicular to the horizontal longitudinal axis of the adaptor. The tooth has a tip at its front end for digging and a socket at its rear end that is configured to receive the front and intermediate portions of the adaptor. When the tooth is coupled to the adaptor, an opening on the rear end of the tooth aligns with the groove to define a passageway that terminates within the socket of the tooth. The retainer pin is inserted into the passageway to secure the tooth to the adaptor and complete the assembly.

FIELD OF THE INVENTION

The present invention relates to excavating equipment, and more particularly to an adaptor and tooth assembly for a dipper bucket.

BACKGROUND OF THE INVENTION

Excavation practice in construction and mining applications is often most efficiently carried out when ground engaging, penetration attachments (tooth and adaptor assemblies) are securely mounted on the leading digging edge of the excavation dipper bucket and/or excavation equipment. Usually, the adaptor(s) are rigidly attached by either welding or some form of mechanical fastener(s).

This chisel-like assembly reduces the initial contact mass of the bucket edge moving into the material(s) being excavated by focusing the accumulated digging forces at the leading tooth point(s); thereby, maximizing the penetration efficiency of the excavating equipment. The loosened material(s) can then be freely loaded into the excavation bucket or diverted around the assembly when only break-up excavation is the prime motive. Abrasive grinding, multi-directional stresses and shock loading at exceedingly high levels can continuously and abruptly assault the integrity of the tooth and adaptor assembly during any given excavation application.

Canadian Patent 1,243,059 and U.S. Pat. No. 4,481,728 represented the first generation elliptical tooth and adaptor system. This system demonstrated the user of a three-piece system in mining applications. This system enabled the user to replace the primary consumable tooth separate from the fixed carrier adaptor. Any number of consumable teeth could then be readily fitted to the adaptor and replaced as each became worn out.

Although the prior art disclosing the first generation elliptical tooth and adaptor system was functional, this system required certain installation and removal techniques that reduced its use in the field. Some of the shortcomings of this prior art include the use of an oversized locking pin that incorporated compressive elastomeric material vulcanized between two rigid members of the locking pin. Excessive force had to be applied by a sledgehammer to sufficiently compress the pin to permit full insertion into a smaller hole that received the lock pin. Installation and removal of the locking pin was also time consuming and physically difficult, particularly if the head of the pin became flattened (mushroom shaped) from repeated hammer blows. The arduous practice of changing out worn teeth and installing new teeth eventually became a safety concern. This original design is no longer acceptable to maintenance workers in certain mining applications. In addition, several other features of this design eventually became a concern.

The first generation elliptical locking pin was dependent upon the physical properties of the vulcanized elastomeric material to carry out its required job of maintaining the tooth fully on the adaptor. Deterioration of the elastomeric material was a common occurrence and the structural design of this tooth and adaptor system restricted the possibility of establishing a preferred locking system not so depended on this component. This type of locking pin was not reusable.

Extreme flowing pressures (several tons) of excavated materials beneath the shovel bucket tended to force the original style of lock pin upward and out of the locked position. Occasionally, these pins would actually be forced completely out and the tooth would fall off.

The first generation elliptical system was designed with an aligning common through hole located centrally in both mated structural members when the tooth was fully fitted to the adaptor. The resulting aligned through holes formed an opening to accept the locking pin. The loss of structural mass in the tooth sidewalls weakened this component, and occasionally, the tooth would break when subjected to severe digging applications.

The first generation elliptical system was designed with the tooth not being completely stable while resting on the adaptor and without the lock pin installed. If a maintenance worker unintentionally bumped an unlocked tooth, it could easily slide off, resulting in an injury to the worker.

Other prior art based on the above-noted system had gaps on the assembled tooth and adaptor, and within and around the lock pinholes. This condition can leave the mating fit surfaces of the assembly, the lock pin bearing support surfaces and its related structural members vulnerable to the extreme flowing pressures (several tons) of excavated materials that are readily forced into these gaps. The abrasive qualities of the ore, combined with any movement between the assembled components during the excavation process create an aggressive grinding effect that deteriorates these important dimensional load-bearing surfaces. The resulting wear can contribute to a “loose fit” condition affecting all three assembled components. This condition is especially true when certain “self-lubricated” and highly abrasive ores such as tar sand are being excavated. These ores have the inherent ability to quickly enter all gaps and internal aspects of the mated assembly. If the retainer lock pin does become loose and falls out, the tooth and adaptor can uncouple, leaving the less wear-resistant adaptor male mating nose exposed to harsh wear from the continuing excavation process.

It is, therefore, desirable to have a tooth and adaptor assembly for a dipper bucket that overcomes the shortcomings of the prior art described above.

SUMMARY OF THE INVENTION

The present invention is a tooth and adaptor assembly for a dipper bucket. In a representative embodiment, the assembly comprises an adaptor having a front portion, an intermediate portion and a rear portion. The rear portion is adapted for attaching to a dipper bucket as well known to those skilled in the art. The intermediate portion extends between the front and rear portions and has a substantially circular base adjacent to the rear portion. The intermediate portion tapers or narrows in cross-section from its base to the front portion. Preferably, the intermediate portion has an elliptical cross-section. The front portion has a substantially flat front end. The exterior surface of the intermediate portion has a portion of its surface that is substantially planar thereby making the intermediate portion roughly D-shaped in cross-section. A groove is disposed along the planar surface, the groove being perpendicular to a longitudinal axis passing through the center of the front, intermediate and rear portions. Preferably, the groove is rectangular in cross-section.

The assembly also comprises a tooth having a front tip portion adapted for excavating and an enlarged rear portion extending from the front end. The enlarged rear portion comprises a top surface and a socket configured to accommodate the front and intermediate portions of the adaptor in a coupled position. Specifically, the socket has an opening adapted to mate with the base of the intermediate portion and a bottom with a flat surface to mate with the front portion. The socket has an interior wall surface that is initially cylindrical at the entrance and then tapers to the bottom, the interior wall surface having a portion that is planar such that it mates with the exterior surface of the intermediate portion of the adaptor. The enlarged rear portion of the tooth also has an opening, which is offset to one side on the top surface. The opening is in alignment with the adaptor groove when the tooth is fully seated on the adaptor thereby defining a passageway that extends from the top surface and terminates within the entrance of the tooth socket. A retainer pin inserted into the passageway and driven downwardly towards a “home” latched position secures the tooth on the adaptor. The retainer pin can be removed by urging it upwardly out of the passageway.

Accordingly, the present invention relates to an assembly of three interlocking components—a tooth, an adaptor and retainer pin. The present invention may be characterized by the elements as set forth below.

In one embodiment, the present invention utilizes an offset, substantially vertical retainer pin whereby installation and removal of the retainer pin is performed from the top surface of the tooth. There is no bottom through-hole necessary in the bottom of the tooth to “drift” the retainer pin out in order to disassemble the tooth from the adaptor. This design prevents entry of highly pressurized compaction forces from beneath that can force the typical base exposed retainer pin(s) upward and out of their latched position.

In another embodiment, the present invention provides an enclosed assembly comprising three components including a tooth, an adaptor and a retainer pin. The components are configured in such a way that the mated surfaces of the assembled components minimize debris from entering certain areas of the coupled and latched tooth and adaptor assembly. In another representative embodiment, the retainer pin has an enlarged head with a bottom surface having a beveled seating collar completely around and beneath the head. The head is adapted to cover the entirety of the retainer pin opening and to mate with the tooth top surface so as to prevent debris from entering the passageway. The head of the retainer pin does have some exposure to falling excavated debris that can assist in maintaining the retainer pin in its “home” latched position.

In another representative embodiment, the adaptor front portion has a rectangular front end and enlarges in cross-section towards the substantially circular base of the intermediate portion. The intermediate portion incorporates a ¾ round cylindrical shank having a flat side surface containing the groove, which is formed thereon. The front and intermediate portions are adapted to conform to an interior configuration of the tooth socket so as to prevent the tooth from rotating on the adaptor in the coupled position. Accordingly, the tooth remains stable on the adaptor while the maintenance worker is performing the tooth change-out. The possibility of the unlatched tooth sliding off the adaptor is virtually eliminated and this makes for safer working conditions.

In view of the complementary shapes of the front and intermediate portions of the adaptor and the tooth socket, the shock and bearing loads are more effectively distributed throughout the assembly. The front and intermediate portions form multi-directional load-bearing surfaces so as to reduce the possibility of tooth and/or adaptor nose breakage. The cylindrical shank also complements the overall load carrying capabilities of the assembly and the physical mass of the shank more than compensates for the loss of structural material given up to the groove that forms the passageway for the retainer pin.

The tooth and adaptor assembly of the present invention provides additional thrust-load bearing capacity with respect to forward directional movement of the assembly mounted on the excavation bucket and/or equipment. In particular, the present invention minimizes the amount of displacement that can occur between the tooth and the adaptor thereby reducing undesirable movement of the retainer pin within the passageway.

It is an object of the present invention to provide a tooth and adaptor assembly for a dipper bucket that is easily serviced. The tooth and adaptor assembly may be disassembled and reassembled with ease, without the need for excessive force applied by sledgehammers or the like. The retainer pin may be moderately tapped into the passageway formed when the tooth is fully seated on the adaptor to the “home” latched position with an ordinary machine hammer. A typical pry bar, or a similar tool, can easily remove the retainer lock-pin from its “home” latched position. One of the advantages of the retainer pin of the present invention is that it is not dependent on an elastomeric material to supports its primary function of keeping latched and maintaining the coupled position of the tooth on the adaptor. Accordingly, the retainer pin may be reused over the course of several tooth change outs, if necessary.

Broadly stated, one aspect of the present invention is a tooth and adaptor assembly for a dipper bucket, comprising: an adaptor comprising a rear portion adapted for attaching to a dipper bucket, a front portion having a substantially flat front end, and a tapered intermediate portion having an exterior surface and a substantially circular base adjacent to said rear portion, said intermediate portion narrowing in cross-sectional area towards said front portion, said intermediate portion further comprising a substantially planar surface on a portion of its exterior surface and a groove traversing said planar surface, said groove substantially perpendicular to a longitudinal axis passing through the center of said front, intermediate and rear portions; a tooth having a front tip portion adapted for excavating and an enlarged rear portion having a top surface, said enlarged rear portion forming a socket adapted to complement said front and intermediate portions of said adaptor, said socket having an entrance that is substantially circular to mate with the base of said intermediate portion, a bottom with a substantially flat surface to mate with the flat front end of said front portion and a tapered interior wall surface narrowing from said entrance to said bottom, a portion of said interior wall surface being substantially planar to mate with the planar surface portion of said intermediate portion whereby said tooth fits securely on said adaptor and engages substantially the entire outer surface of said front and intermediate portions of said adaptor, said tooth further comprising an opening on said enlarged rear portion that substantially aligns with said groove to define a passageway when said tooth is substantially engaged with said adaptor; and a retainer pin adapted to be inserted through said opening into said passageway to secure said tooth to said adaptor.

Other objects, features and advantages of the present invention will become clear from the following detailed description, when read in associated with the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the present invention showing the tooth uncoupled from the adaptor that is mounted to a dipper bucket.

FIG. 2 is a perspective view of an embodiment of the present invention showing the tooth being seated on the adaptor and secured with the retainer pin.

FIG. 3 is a side elevational view of an embodiment of the present invention showing the tooth coupled to the adaptor and secured with the retainer pin.

FIG. 4 is a top plan view of an embodiment of the present invention showing the tooth coupled to the adaptor and secured with the retainer pin.

FIG. 5 is a side elevational view of an embodiment of the present invention showing the tooth and the adaptor in an uncoupled position.

FIG. 6 is a top plan view of an embodiment of the present invention showing the tooth and the adaptor in an uncoupled position.

FIG. 7 is a side elevational cross-section view of the tooth in accordance with an embodiment of the present invention shown along sections lines A-A.

FIG. 8 is a side elevational cross-section view of the tooth in accordance with an embodiment of the present invention shown along section lines B-B.

FIG. 9 is a top plan cross-sectional view of the tooth in accordance with an embodiment of the present invention shown along section lines C-C.

FIG. 10 is a side elevational view of the adaptor in accordance with an embodiment of the present invention.

FIG. 11 is a top plan view of the adaptor in accordance with an embodiment of the present invention.

FIG. 12 is a front elevational view of the retainer pin in accordance with an embodiment of the present invention.

FIG. 13 is a right side elevational view of the retainer pin in accordance with an embodiment of the present invention.

FIG. 14 is a front elevational cross-section view of an embodiment of the present invention shown along section lines D-D.

FIG. 15 a front elevational cross-section view of the retainer pin in accordance with an embodiment of the present invention as shown within section line E.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 and 2, a representative embodiment of the present invention is shown. Tooth/adaptor assembly 10 broadly consists of excavation tooth 12, adaptor 14 and retainer pin 16. Adaptor 14 comprises an elongated U-shaped member that attaches to dipper bucket 18 on bucket lip 19 as well known to those skilled in the art. Tooth 12 is seated onto adaptor 14 and secured by retainer pin 16 that is inserted through opening 20 to fit snugly into groove 22. Tooth 12 is designed to bear the brunt of the wearing forces caused by excavating and will wear out over time. As tooth 12 wears out to the point that it is no longer serviceable, tooth 12 can be removed from adaptor 14 by extracting retainer pin 16 from opening 20 and sliding tooth 12 off of adaptor 14 so that a new tooth 12 may be installed.

Referring to FIGS. 3 and 4, side and top views of assembly 10 is shown with tooth 12 fully seated on adaptor 14. Tooth 12 has a pointed top 24 designed for excavating is shown secured to adaptor 14 with retainer pin 16 seated in opening 20. In a preferred embodiment, tooth 12 comprises a raised deflector 26 that is positioned at least partially around opening 20. Deflector 26 is, preferably, L-shaped and acts to prevent debris from thrusting directly against the top of retainer pin 16 during excavation operations.

Referring to FIGS. 5 and 6, side and top views of assembly 10 is shown with tooth 12 uncoupled from adaptor 14. Adaptor 14 comprises base portion 28 that is generally circular in cross-section, intermediate elliptical tapered cone portion 38 and front block portion 59. Disposed on a side of base and intermediate portions 28 and 38 is flat surface 32 that gives base portion 28 and intermediate portion 38 a generally D-shaped or ¾ round cross-section. Flat surface 32 has a planar axis that is tilted off-vertical as it slopes inwardly from top to bottom on adaptor 14. Traversing across flat surface 32 is groove 22 that is, preferably, substantially perpendicular to longitudinal axis 11 of assembly 10. To couple tooth 12 and adaptor 14 together, tooth 12 comprises socket 34 that receives front, intermediate and base portions 59, 38 and 28 of adaptor 14. When tooth 12 is seated on adaptor 14, thrust bearing surface 36 of tooth 12 contacts thrust bearing surface 30 of adaptor 14. Load forces passing from adaptor 14 to tooth 12 and from tooth 12 back to adaptor 14 are transmitted via these uniform mated fit surfaces. Furthermore, when tooth 12 is seated on adaptor 14, opening 20 aligns with groove 22 to provide a substantially continuous passageway 21 for receiving retainer pin 16.

In FIGS. 7 and 8, side cross-sectional views of tooth 12 are shown. FIG. 9 illustrates a top plan cross-sectional view of tooth 12. Tooth 12 comprises socket-opening 34 that has a substantially circular interior load bearing surface 40 to match base 28 of adaptor 14. Transition cavity 46 is a relief groove that separates load surface 40 from elliptical cone surface 42. Transition cavity 44 is another relief groove that separates elliptical cone surface 42 from block sidewalls 50 a to 50 d. Relief cavities 44 and 46 are relatively rectangular in shape and offers additional relief clearance for adaptor transition zone edges 37 and 39 on tooth 12 when it is fully seated on adaptor 14.

Referring to FIG. 9, sidewalls 50 a to 50 d and primary thrust bearing surface 48 provide an opening to receive front block 59 of adaptor 14 in a sliding fit. Preferably, front block 59 and the opening defined by sidewalls 50 a to 50 d are rectangular. Cone surface 42 and circular base 40 further comprises flat surface 52 that gives this intermediate portion of socket 34 a generally D-shaped or ¾ round cross-section. Groove 54 traverses planar surface 52 and is generally perpendicular to the horizontal axis of tooth 12. Groove 54 comprises sidewalls 55 a to 55 c and aligns with groove 22 on tooth 12 to provide the substantially continuous passageway 21 for receiving retainer pin 16. Sidewall 55 a serves as a flat bearing surface to accept moderate thrust loads from retainer pin 16 during excavation operations. At the bottom of groove 54 is mitre surface 56 that marks the end of passageway 21. In a representative embodiment of the present invention, passageway 21 is rectangular in cross-section.

Referring to FIGS. 10 and 11, side and top views of adaptor 14 are shown, respectively. Adaptor 14 comprises of adaptor base 28, which is generally circular, elliptical body 38 and front block 59. Front block 59 is preferably, rectangular and comprises of sidewalls 60 a to 60 d and primary thrust surface 58. Elliptical body 38 tapers from transition 37 to transition 39. Offset flat surface 32 is disposed on elliptical body 38 and adaptor base 28. Groove 22 is disposed on flat surface 32 and is generally perpendicular to the horizontal axis of adaptor 14. Groove 22 aligns with groove 54 of tooth 12 when tooth 12 is fully seated onto adaptor 14. Front block 59 is adapted for a sliding fit with the bottom of socket 34 which is defined by sidewalls 50 a to 50 d and thrust bearing surface 48. Preferably, adaptor front block 59 has a generally rectangular cross section, with flat front mating surface 58 having a width that is greater than its height, that is, top and bottom mating surfaces 60 a and 60 c wider than flat side mating surface 60 b and 60 d.

Front and side views of retainer pin 16 are shown in FIGS. 12 and 13. Retainer pin 16 comprises sidewalls 64 a and 64 d, bottom mitre surface 68, pin head 62 and lift lug 66. In a representative embodiment, pin head 16 has a bottom surface adapted to cover the entirety of opening 20 and mate with the top surface of tooth 12 so as to prevent debris from entering passageway 21. In a representative embodiment, pin head 62 further comprises of bevelled edges 76 that uniformly mate with the edges of opening 20. This uniform metal-to-metal surface contact is maintained by the downward magnetic pull, as described below, that encloses passageway 21 and the interior of assembly 10. Positioned on bottom surface 68 is magnet 70. Magnet 70 urges retainer pin 16 into passageway 21 as magnet 70 is attracted to groove bottom surface 56. To further keep retainer pin 16 within passageway 21, sidewall 64 d further comprises spring-loaded plunger 72 that latches into complementary recess 78 in passageway 21. In a representative embodiment of the present invention, plunger 72 is a setscrew. Lubrication holes 74 disposed transversely through the body of retainer pin 16 retain lubricant that reduces wear from potential thrust loads applied to retainer pin 16 during excavation operations. To remove retainer pin 16 from passageway 21, a pry bar or tool is used to pry up on lift lug 66 on pin head 62. Retainer pin 16 is of a rigid construction and may be manufactured from steel or alloys having suitable strength and wear properties.

In FIGS. 14 and 15, front cross-sectional views of assembly 10 are shown. When retainer pin 16 is inserted into passageway 21, plunger 72 compresses into the body of retainer pin 16 and bottom surface 68 and magnet 70 contact bottom surface 56 in socket 34. Once retainer pin 16 is fully inserted into passageway, plunger 72 extends into recess 78 defined by the transition between adaptor base 28 and load bearing surface 40 of tooth 12. Accordingly, retainer pin 16 is held in position by magnet 70 contacting bottom surface 56 and plunger 72 extending into recess 78. The downward magnetic pull derived from magnet 70 assists in keeping retaining pin 16 fully seated and stabilized in passageway 21. Retainer pin 16 is marginally smaller than opening 20 and is readily received in sliding fit within passageway 21. Passageway 21 permits full insertion of retainer pin 16 therein and bottom mitre surface 68 bottoms out on groove bottom surface 56. All internal surfaces of passageway 21 can transfer varying thrust loads via retainer lock pin external sidewalls 64 a to 64 d while retainer pin 16 securely maintains the fully coupled position of tooth 12 on adaptor 14 during excavation operations.

Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention. The terms and expressions used in the preceding specification have been used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described or portions 

1. A tooth and adaptor assembly for a dipper bucket, comprising: a) an adaptor comprising: i) a rear portion adapted for attaching to a dipper bucket; ii) a front portion having a substantially flat front end, and iii) a tapered intermediate portion having an exterior surface and a substantially circular base adjacent to said rear portion, said intermediate portion narrowing in cross-sectional area towards said front portion, said intermediate portion further comprising a substantially planar surface on a portion of its exterior surface and a groove traversing said planar surface, said groove substantially perpendicular to a longitudinal axis passing through the center of said front, intermediate and rear portions; b) a tooth having a front tip portion adapted for excavating and an enlarged rear portion having a top surface, said enlarged rear portion forming a socket adapted to complement said front and intermediate portions of said adaptor, said socket having an entrance that is substantially circular to mate with the base of said intermediate portion, a bottom with a substantially flat surface to mate with the flat front end of said front portion and a tapered interior wall surface narrowing from said entrance to said bottom, a portion of said interior wall surface being substantially planar to mate with the planar surface portion of said intermediate portion whereby said tooth fits securely on said adaptor and engages substantially the entire outer surface of said front and intermediate portions of said adaptor, said tooth further comprising an opening on said enlarged rear portion that substantially aligns with said groove to define a passageway when said tooth is substantially engaged with said adaptor; and c) a retainer pin adapted to be inserted through said opening into said passageway to secure said tooth to said adaptor.
 2. The assembly as set forth in claim 1 wherein said bottom of said socket and said front portion of said adaptor are rectangular in cross-section and are adapted to couple together in sliding fit.
 3. The assembly as set forth in claim 1 wherein said enlarged rear portion of said tooth further comprises a raised deflector extending around at least a portion of said opening for deflecting debris away from said passageway and retainer pin.
 4. The assembly as set forth in claim 1 wherein said planar surface portion of said intermediate portion is offset from a vertical axis sloping inwardly from top to bottom on said intermediate portion.
 5. The assembly as set forth in claim 4 wherein said retainer pin comprises a body conforming to the shape of said passageway and an enlarged head with a bottom surface adapted to cover said opening and mate with said top surface so as to prevent debris from entering said passageway.
 6. The assembly as set forth in claim 5 wherein said retainer pin further comprises a biasing element that compresses into said retainer pin as it is driven into said passageway, said biasing element extending outwardly into a complementary recess when said retainer pin is fully inserted in said passageway.
 7. The assembly as set forth in claim 6 wherein said retainer pin further comprises a magnet to urge said retainer pin downwardly in a latched position within said passageway.
 8. The assembly as set forth in claim 5 wherein said retainer pin further comprises a prying element on said enlarged head for prying said retainer pin out of said passageway.
 9. The assembly as set forth in claim 5 wherein said retainer pin further comprises at least one hole disposed through said body for containing a lubricant.
 10. The assembly as set forth in claim 1 wherein said passageway is rectangular in cross section and is further configured to receive said retainer pin therein. 